I am trying to flash one of these too, but I am not quite sure of what I'm doing when it comes to tftp. I'm following the generic flashing instructions and I have a few questions:
1. Does this device have a tftp server in it? In other words I want to confirm if I should follow the "Bootloader contains TFTP client" procedure or the "Bootloader contains TFTP server" procedure.
2. From your pc/laptop did you use the 192.168.0.66 address for `setenv ipaddr` or `setenv serverip` ?
The procedure to flash this model is well explained in the post by 'iorx' and I succeeded on the first try. Many thanks to him.
This model comes with TFTP client in the bootloader. You need to run TFTP server on your PC.
When the AP turns on with the reset button pressed, it configures itself as 192.168.0.86 and starts TFTP client. Then it looks for TFTP server at 192.168.0.66 and requests for wa901ndv4_tp_recovery.bin file if the server is found. The TFTP session takes just a few seconds to download the firmware file.
It is not necessary to login with serial port to change the IP address if you change the PC IP address accordingly.